EcoR1 Capital, LLC
In its 13F for Q1 2024 (holdings as of March 31, 2024, filed May 15, 2024), EcoR1 Capital, LLC reported 54 stock positions worth $3.9 billion. Its top holding was Apellis Pharmaceuticals (APLS) at 17.0% of the portfolio, followed by Prothena (PRTA, 7.3%) and Arvinas (ARVN, 7.1%). Compared with Q4 2023, it opened 16 new positions, sold out of 9, added to 8 and reduced 3. The biggest buy was Sarepta Therapeutics (SRPT, shares +131%) and the biggest sale an exit from Mirati Therapeutics (MRTX).
- Most Recent 13F
- Q2 2026
- Location
- San Francisco, CA
- CIK
- 0001587114
- Portfolio Value
- $3.9B (Q1 2024)
- SEC Filing
- 0000935836-24-000391 ↗ filed May 15, 2024
Holdings Value
Holdings 54 stocks · $3.9B
| APLS Apellis Pharmaceuticals Inc. | 16.97% | 11,357,425 | $667.6M | Add +1.6% |
| PRTA Prothena Corp. PLC | 7.29% | 11,584,280 | $286.9M | No change |
| ARVN Arvinas Inc. | 7.06% | 6,726,491 | $277.7M | No change |
| SRPT Sarepta Therapeutics Inc. | 6.32% | 1,919,835 | $248.5M | Add +130.5% |
| CRNX Crinetics Pharmaceuticals Inc. | 4.95% | 4,155,375 | $194.5M | Add +106.5% |
| LKFT Lakefront Biotherapeutic-ADR filed as GALAPAGOS NV | 4.71% | 5,756,268 | $185.4M | No change |
| ANAB Anaptysbio Inc. | 4.31% | 7,521,024 | $169.4M | No change |
| ZYME Zymeworks Inc. | 3.59% | 13,437,473 | $141.4M | No change |
| KURA Kura Oncology Inc. | 3.15% | 5,806,871 | $123.9M | No change |
| JAZZ Jazz Pharmaceuticals PLC | 3.10% | 1,013,952 | $122.1M | No change |
| XNCR Xencor Inc. | 3.00% | 5,330,416 | $118.0M | Add +0.9% |
| ACAD Acadia Pharmaceuticals Inc. | 2.82% | 5,991,479 | $110.8M | No change |
| TNGX Tango Therapeutics Inc. | 2.69% | 13,330,736 | $105.8M | No change |
| IMNM Immunome Inc. | 2.43% | 3,879,415 | $95.7M | No change |
| CRSP Crispr Therapeutics AG | 2.41% | 1,389,276 | $94.7M | New |
| MERSANA THERAPEUTICS INC | 2.21% | 19,364,688 | $86.8M | No change |
| MORF Morphic Holding Inc. | 2.13% | 2,384,384 | $83.9M | Add +1028.6% |
| NUVB Nuvation Bio Inc. | 1.78% | 19,209,643 | $69.9M | No change |
| NGNE Neurogene Inc. | 1.65% | 1,271,342 | $64.7M | No change |
| CNTA Centessa Pharmaceuticals Ltd. | 1.61% | 5,618,779 | $63.5M | No change |
| ORIC Oric Pharmaceuticals Inc. | 1.19% | 3,418,068 | $47.0M | No change |
| ADAPY Adaptimmune Therapeutics-ADR | 1.10% | 27,404,070 | $43.3M | New |
| TCRX Tscan Therapeutics Inc. | 1.01% | 5,000,000 | $39.7M | No change |
| VYGR Voyager Therapeutics Inc. | 0.93% | 3,917,546 | $36.5M | Add +1.7% |
| THRD Third Harmonic Bio Inc. | 0.76% | 3,182,444 | $30.0M | No change |
| NMRA Neumora Therapeutics Inc. | 0.72% | 2,071,450 | $28.5M | No change |
| CLDX Celldex Therapeutics Inc. | 0.69% | 650,000 | $27.3M | New |
| ITOS Iteos Therapeutics Inc. | 0.69% | 1,999,249 | $27.3M | Add +79.3% |
| LENZ Lenz Therapeutics Inc. | 0.69% | 1,219,774 | $27.2M | New |
| AVIR Atea Pharmaceuticals Inc. | 0.63% | 6,145,861 | $24.8M | Reduce -12.2% |
| ALEC Alector Inc. | 0.62% | 4,056,548 | $24.4M | No change |
| EWTX Edgewise Therapeutics Inc. | 0.58% | 1,250,385 | $22.8M | Reduce -64.2% |
| NKTX Nkarta Inc. | 0.55% | 2,000,000 | $21.6M | New |
| PHVS Pharvaris NV | 0.53% | 900,000 | $20.8M | No change |
| PCVX Vaxcyte Inc. | 0.52% | 300,000 | $20.5M | New |
| MDGL Madrigal Pharmaceuticals Inc. | 0.51% | 75,000 | $20.0M | New |
| RNAM Avidity Biosciences Inc. | 0.49% | 757,576 | $19.3M | New |
| OVID Ovid Therapeutics Inc. | 0.47% | 6,117,400 | $18.7M | No change |
| VERV Verve Therapeutics Inc. | 0.42% | 1,250,000 | $16.6M | No change |
| KROS Keros Therapeutics Inc. | 0.32% | 187,500 | $12.4M | New |
| DYN Dyne Therapeutics Inc. | 0.31% | 427,039 | $12.1M | New |
| KYTX Kyverna Therapeutics Inc. | 0.28% | 450,000 | $11.2M | New |
| GOSS Gossamer Bio Inc. | 0.28% | 9,195,404 | $10.9M | No change |
| ALLOVIR INC | 0.22% | 11,294,585 | $8.5M | New |
| KOD Kodiak Sciences Inc. | 0.22% | 1,613,600 | $8.5M | New |
| GBIO Generation Bio Co. | 0.21% | 2,046,867 | $8.3M | No change |
| ATRA Atara Biotherapeutics Inc. | 0.18% | 10,167,043 | $7.1M | Add +1.0% |
| PRQR Proqr Therapeutics NV | 0.17% | 2,884,357 | $6.6M | Reduce -3.2% |
| ALGS Aligos Therapeutics Inc. | 0.16% | 6,389,468 | $6.3M | No change |
| ARQT Arcutis Biotherapeutics Inc. | 0.13% | 500,000 | $5.0M | New |
| PRME Prime Medicine Inc. | 0.12% | 700,000 | $4.9M | New |
| HOOKIPA PHARMA INC | 0.08% | 4,595,024 | $3.3M | No change |
| PMVP PMV Pharmaceuticals Inc. | 0.02% | 566,879 | $964K | No change |
| ALPN Alpine Immune Sciences Inc. | 0.00% | 1,000 | $40K | New |
Options reported separately and not counted above: KURA calls ($14.9M), KOD calls ($269K).
Other holdings (3): bonds, preferreds, convertibles and warrants · $5.0M (not counted above)
Total filed on the 13F, all lines: $3.9B.
Portfolio Sells Q4 2023 → Q1 2024
| MRTX Mirati Therapeutics Inc. | Sold out | 0.00% | −11.29 |
| ARGX Argenx SE - ADR | Sold out | 0.00% | −2.98 |
| GRPH Graphite Bio Inc. | Sold out | 0.00% | −0.58 |
| SYRE Spyre Therapeutics Inc. | Sold out | 0.00% | −0.50 |
| EWTX Edgewise Therapeutics Inc. | Reduce -64.2% | 0.58% | −0.41 |
| RVMD Revolution Medicines Inc. | Sold out | 0.00% | −0.10 |
| NGM NGM Biopharmaceuticals Inc. | Sold out | 0.00% | −0.05 |
| ALLK Allakos LLC | Sold out | 0.00% | −0.05 |
| TYRA Tyra Biosciences Inc. | Sold out | 0.00% | −0.05 |
| PHAT Phathom Pharmaceuticals Inc. | Sold out | 0.00% | −0.05 |
| PRQR Proqr Therapeutics NV | Reduce -3.2% | 0.17% | +0.01 |
| AVIR Atea Pharmaceuticals Inc. | Reduce -12.2% | 0.63% | +0.08 |
Portfolio Buys Q4 2023 → Q1 2024
| SRPT Sarepta Therapeutics Inc. | Add +130.5% | 6.32% | +4.23 |
| CRNX Crinetics Pharmaceuticals Inc. | Add +106.5% | 4.95% | +3.08 |
| CRSP Crispr Therapeutics AG | New | 2.41% | +2.41 |
| MORF Morphic Holding Inc. | Add +1028.6% | 2.13% | +1.98 |
| ADAPY Adaptimmune Therapeutics-ADR | New | 1.10% | +1.10 |
| CLDX Celldex Therapeutics Inc. | New | 0.69% | +0.69 |
| LENZ Lenz Therapeutics Inc. | New | 0.69% | +0.69 |
| NKTX Nkarta Inc. | New | 0.55% | +0.55 |
| PCVX Vaxcyte Inc. | New | 0.52% | +0.52 |
| MDGL Madrigal Pharmaceuticals Inc. | New | 0.51% | +0.51 |
| RNAM Avidity Biosciences Inc. | New | 0.49% | +0.49 |
| ITOS Iteos Therapeutics Inc. | Add +79.3% | 0.69% | +0.38 |
| KROS Keros Therapeutics Inc. | New | 0.32% | +0.32 |
| DYN Dyne Therapeutics Inc. | New | 0.31% | +0.31 |
| KYTX Kyverna Therapeutics Inc. | New | 0.28% | +0.28 |
| ALLOVIR INC | New | 0.22% | +0.22 |
| KOD Kodiak Sciences Inc. | New | 0.22% | +0.22 |
| ARQT Arcutis Biotherapeutics Inc. | New | 0.13% | +0.13 |
| PRME Prime Medicine Inc. | New | 0.12% | +0.12 |
| XNCR Xencor Inc. | Add +0.9% | 3.00% | +0.09 |
| VYGR Voyager Therapeutics Inc. | Add +1.7% | 0.93% | +0.08 |
| ATRA Atara Biotherapeutics Inc. | Add +1.0% | 0.18% | +0.05 |
| ALPN Alpine Immune Sciences Inc. | New | 0.00% | +0.00 |
| APLS Apellis Pharmaceuticals Inc. | Add +1.6% | 16.97% | −0.41 |
Options Activity Q4 2023 → Q1 2024
Calls and puts are listed by the shares they cover; their value is not part of the stock holdings above.
Notes & Other Activity Q4 2023 → Q1 2024
| NAMSW Newamsterdam Pharma Co. NV-27 | *W EXP 99/99/999 | Sold out | 66,665 | $745Kbefore exit |
Bonds, preferreds, convertibles and warrants; not part of the stock holdings or percentages above.
All Filings
| Quarter | Positions | 13F Reported Value | Top Holdings |
|---|---|---|---|
| Q2 2026 | 30 | $2.0B | ZYME, ANAB, AKTS, CGON, ETON |
| Q1 2026 | 28 | $2.3B | ZYME, ANAB, JAZZ, CNTA, CRNX |
| Q4 2025 | 26 | $2.2B | ZYME, ANAB, JAZZ, CRNX, CNTA |
| Q3 2025 | 28 | $2.1B | ZYME, ANAB, QURE, JAZZ, CRNX |
| Q2 2025 | 34 | $1.7B | ZYME, APLS, JAZZ, ANAB, CRNX |
| Q1 2025 | 42 | $1.7B | APLS, JAZZ, ZYME, ANAB, CRNX |
| Q4 2024 | 53 | $2.5B | APLS, ZYME, CRNX, JAZZ, PRTA |
| Q3 2024 | 60 | $2.9B | APLS, ANAB, CRNX, PRTA, JAZZ |
| Q2 2024 | 52 | $3.3B | APLS, PRTA, SRPT, ANAB, CRNX |
| Q1 2024 | 54 | $3.9B | APLS, PRTA, ARVN, SRPT, CRNX |